Crane



Oct. 30, 1962 c. F. STONE CRANE Filed July 20, 1959 5 Sheets-Sheet 1A ar/ F Ehm@ Oct. 30, 1962 c. F. STONE 3,061,109

CRANE Filed July 20. 1959 5 Sheets-Sheet 2 Car] fme b 777 l, WHEJS C. F. STONE Oct. 30, 1962 CRANE 5 Sheets-Sheet 3 Filed July 20. 1959 v o o v o o 77-7VE 7-/7L/77-f b 'Mlw' Car/ F /Szme ,g m; 57H95# Oct. 30, 1962 C. F. STONE CRANE 5 Sheets-Sheet 5 Filed July 20. 1959 .www

Uaf/ E 5m@ ,Wffyg HJQW@ United States Patent C) 3,061,109 CRANE Carl F. Stone, Fruitport, Mich.,.assignor to Manning, Maxwell & Moore, Incorporated, Muskegon, Mich., a. corporation of New JerseyV Filed July 20, 1959, Ser. No. 828,190 13 Claims. (Cl. 212--4) This invention relates generally to cranes, and more specifically to an improved crane of thetype supported on a ship.

Although the Aprinciples of the present invention may be included inV various cranes, a particularly useful application is made in the provision of a gantry crane which is carried on a ship for handling hatch covers thereof. I-Ieretofore, ship-based cranes have not been satisfactory for this purpose.

Accordingly,` it is an object of the presentv invention to provide an improved crane.

Another object of the present invention is to provide a crane which is particularly suited for shipboard use, and which particularly is constructed for the efficient handling of a cover which closesa ship-hatch.

A still further object of the present invention isto provide means for a crane which limits the upward movement of an article being hoisted by the crane.

Yet another .object `of the present invention is to provide a crane which may be conveniently utilized in the painting of the other side of a ship.

Another object of the present invention is to provide a crane wherein certain driven parts thereof are powered by hydraulic means.

A still further object of the present invention is to provide a crane having such controls and accessories as are necessary for the ehicient handling of hatch covers on board a ship.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles ofthe present invention is shown by way of illustrative example.

On the drawing:

FIGURE l is an elevational view, partly broken away, of a hatch cover crane provided in accordancewith the principles of the present invention;

FIGURE 2 is a top view of the structure shown in FIGURE l;

FIGURE 3 is an enlarged end view, partially broken away, of the crane structure shown in FIGURE l;

FIGURE 4 is a schematic diagram illustrating the structure employed for moving the hooks of the crane vertically;

FIGURE 5 is an enlarged view, partially in section, and partly broken away, taken along line V-V of FIG- URE 1;

FIGURE 6 is anenlarged fragmentary portion, partly in section, of the structure shown in FIGURE 3;

FIGURE 7 is an enlarged fragmentary view of a portion of the struct-ure shown in FIGURE 2, and comprising the operators platform;

FIGURE 8 is an enlarged elevational view of a fragmentary portion of the structure shown in FIGURE l, with certain details omitted for the purpose of clarity;

FIGURE 9 is an enlarged cross sectionalv view taken along line IX-IX of FIGURE 8; and

`FIGURE 10i is a schematic diagram of the hydraulic system of the structure shown in FIGURE l.

As shown in the drawings:

The principles of this invention are particularly useful when embodied in a gantry crane such as illustrated in FIGURE l, generally indicated by the numeral 10. The

3,061,109 Patented Oct. 30., 1962 ICC crane includes a bridge assembly 11, having fa pair of hooks 12 and 13, which are provided with means for moving the hooks vertically generally indicated at 14 together with other devices and components that form the hydraulic system diagrammatically shown in FIG- URE l0.

The crane 1t)V is supported on a pair of rails 15, 16 which, in turn, are supported on Vthe deck 17 of a shiphull closely adjacent to and intermediate of the sides 18, 19 of the ship. Intermediate the rail 1'7 and the side 19 of the ship there is a walkway 20, which is comparatively or relatively narrow. The ship diagrammatically shown `includes a'hatch opening 21 which is providedl with a hatch coverl 22 having eye-pads 23 for being engaged by the hooks 12, 13. For purpose of identication only, the side of the ship 1S isiidentied as the port side and the side 19 as the star-board side of the ship, whereby the view shown in FIGURE l is taken looking ina forward or fore direction. The crane illustrated is relatively large, and,V by Way of example, the actual distance between the rails 15,16 is 58 feet.

Thebridge assembly 11 extendstransversely to the rails 15, v16, and thus is clearly rather elongated. The bridge assembly r11 mainly comprises a pair of beams 24, 25 which are spaced from each other in a fore and aft direction. Certain components, presently to be described, are supported on the upper surface of the beams 24, 2'5, while the lower surfaces thereof support a pairof resilient bumpers 26, 26, such as of rubber, and provided with a suitable bracket for the attachment and backingup thereof. The bumpers 26, 2-6 are disposed adjacent to the hooks 112, 13 whereby an article raised by the hooks, such as theV hatch cover 22, may engage the bumpers 26.

The beams 24, 25 are supported at each end by a pair of legs 27, 28, best seen in FIGURE 3. As shown in FIGURE 3, the numeral 28 represents the pair of legs or leg assembly which includes individual leg sections 29, and 3). The leg assemblies 28 are each supported on a wheelbase, truck or end carriage 31, and 'are rigidly -secured thereto. Each of the wheelbases or trucks 31 has a pair of wheels 32, 33 of the flanged type which ride on. one ofthe rails. Thus, broadly speaking, each of the legs or leg rsections is provided with a wheel for movable support on the rails.

The leg assemblies 27, 2S arerigidly secured to the beams 24, 25 by any convenient means such as welding to define a self-supporting rigid structure movably supported on the rails 15, 16. The lower surface of the beams 24, 25 and the inner surface of the leg assemblies 27, 2S jointly define a` clearance zone having such height as may be. necessary teclear various elements of ship structure. When the only structure to be cleared cornprises .ahatch cover, which must also be raised, the clearance beneath the bridge assembly y1K1 is of course held to a minimum. Further, it is to be understood thatA the bumpers 26 should extend into such clearance zone.

` Each of the wheels 32 is provided with a drive means generally indicated ..at.33 as best seen in FIGURE.u

The drive means 33 includes a fluidrnotor 34 such as a hydraulic motor, la step-down gear assembly `35 joined i thereto by `a coupling assembly 36 `and delivering power to the wheel` 32 to rotate it in either direction by means of a pair ofl gears `or sprocket wheels 37, 38 and chain 39:-suitably enclosed wi-thin a cover 40. Each of the drive means 33 includes a rotatable wheel or drum 41 best seen in FIGURE A3 about which extends a brake shoe assembly 42 which is biased toward continual en-` gagement with the :drum 41 by a 'spring 43. A hydraulic actuator 44 is connected to the brake shoe `assembly 42 for assisting `and for opposing the spring `43. In the absence `of anyiluid pressure in the actuator 44, the' spring 43 urges the structure 42 into engagement with the drum 41 to thereby brake the associated wheel. The importance of a high-performance brake structure will be apparent due to the fact that the rails 'are inclined a few degrees at each end of the ship. Further the ship may in unusual circumstances be subjected to rolling and pitching.

Not only are the rails 15, 16 subjected to occasional sleet, but in cold weather with high seas it is expected ythat rails of this type would quickly become ice coated. Accordingly, I provide in this combination the feature of a sander 45 supported by one of the leg assemblies 27, 28, for each of the four wheels 32. The detailed structure of each sander does not form a part of this invention. However, each sander is supported and disposed and arranged to discharge sand -to a line 46 to the adjacent rail as best seen in FIGURE 3.

At each end of each of the beams 24, there is provided an outrigger member or assembly 47. The outrigger members 47 shown in FIGURE 1 supported by the beam 24 have the same appearance as the corresponding outrigger members supported on the beam 25. Thus at each end of the bridge assembly 11, there is provided a fore and aft adjacently spaced pair of outrigger members, each of which extends in parallel relation to the bridge. Each of the outriggers 47 is slidably extendable so that the free end may overhang beyond materials to the ship. A locking means or bracket 64a is provided on the beam for stowing the jib crane in fixed position when it is not in use.

As best seen in FIGURE 3, the leg assemblies 27, 28 are each provided with a pair of towing eyes or pads 65a, 65a. By means of these towing eyes, the crane may be towed fore and aft by the ships mooring Winches in case of a crane power failure. The eyes may also be used for securing the crane in stowed position, and be used to move heavy articles horizontally in a line generally parallel 4to Ithe rails. They are also useful in handling the ships mooring lines in its berth.

The hooks 12 and 13 are disposed in fixed positions along the length of the bridge yassembly 11. These positions are intermediate the rails 15, 16 and the hooks depend from the bridge assembly 11. Preferably, the hooks are spaced from each other by a distance equal to the spacing between `the pads 23 on the hatch cover 22. The -detailed structure of each hook is shown in FIGURE 5. A pair of plates 65, 66 are suitably secured to each other in spaced relation by means 67, and a sheave 68 is rotatably supported between the plates 65,

66. A hook element 69 reinforced at 70 is provided with the adjacent side 18, 19 of the ship. To this end, the

detailed structure shown in FIGURES 8 and 9 has been provided. A pair of vertically spaced apertures in the beam 24 receives the threaded ends of `a pair of spacer members 48, 48 which extend through washer-like plates 49, 49 -and are -secured as by a nut and washer assembly 50. In like manner, a rigid plate 51 is secured to the opposite ends of the spacer members 48, 48. A roller 52 having a suitable bearing insert 53 is carried on an enlarged central portion of the spacer members 48 to define a generally rectangular opening intermediate the beam 24 and the plate 51. In this opening, the extendable portion of the outrigger structure, shown to comprise a channel-like material identified at 54 is slidably disposed for extension and retraction. The -supporting structure for the outrigger member is indicated 'as a whole by the numeral 55 and two such structures are included for each of the four outriggers 47.

On the inboard end of each loutrigger 47, there is a stop 56 secured to the upper surface of the channel member 54. To the wall of the beam 24 there is secured a fixed stop 57 against which the stop 56 may engage or -abut to limit inboard movement of the outrigger 47. The stop 56 is engageable with the support structure 55 which is disposed the closer thereto for limiting outward extension of -the outrigger 47. The free or outboard end of the outrigger 47 is provided, in this embodiment, with `an eye 58a from which a load may be supported, for example by block and tackle. It can be seen that a platform can thus be supported at a selected height beyond the adjacent side of the ship, and that by fore and aft movement of the crane as a whole, access to a substantial portion of the side of the ship may thus be had.

As best seen in FIGURES 3 and 8, the instant crane includes a jib crane assembly generally indicated at 58. Two such structures `are provided. One of them is located on the aft side of the starboard end of the bridge assembly 11, and the other jib crane assembly 58 is supported on the forward side of the port end of the bridge assembly 11. A supporting column 59 is secured as by brackets 60, 61 to the adjacent bridge beam, and a boom 62 is horizontally pivoted thereto. Guy means 63 extend from the outboard end of the boom 62 to the upper end of the column 59 for providing further support. At the outboard end of the boom 62 there is provided a small hoist 64, typically electrically operated, and of conventional structure. The jib crane 58 is employed most often for loading and unloading supplies and a pvot pin 71 which extends horizontally in a fore and aft direction, and which pin is xedly secured to the plates 65, 66 as by blocking means 72, '72. The hook element 69 is thus pendulously supported on the pin 7l for slight rocking toward one side of the ship or the other, and suitable washers or bearing inserts generally indicated at 73 may also Abe included therewith. Thus each of the hooks is part of `a sheave-hook assembly wherein the hook element 69 is not rotatable about a vertical axis, but wherein the open end of the hook element opens in a direction parallel to the rails 15, 16 for engagement with `the hatch cover 22 by mere movement of the crane as a whole.

To drive the various driven components of the crane, there is provided in this embodiment a source of pressurized fluid schematically illustrated in FIGURE l by by the numeral 74. This power source is supported on the bridge in spaced relation to the clearance zone beneath the bridge. ln particular, this source 74 of lluid power provides the energy for operating the drive motors 34, the brake actuators 44, and the means 14 for moving the hooks. As best seen in FIGURE 3, there is provided a control station which includes a control panel 75 having control means operable at 76 for the foreward and aft sanders 45, control means indicated at 77 for a motor in the power source 74, control means indicated at 78 `for the hooks, and control means indicated at 79 for the wheel drive motors 34 and brake actuators 44.

For the sake of clarity, the various hydraulic or liuid lines have been omitted from the crane drawings, the mode of routing various fluid lines being well known in the art. In this embodiment, the control panel 75 is secured to the adjacent sander 45, and thereby to the leg structure 28. From this control station, all powdered crane movements are selected. It will be noted that the control panel 75 is disposed relatively close to the deck 17 of the ship. In this embodiment, the starboard wheelbase or 'truck 31 is provided with an operators platform generally indicated at 80, and which is hinged as at 81 (see FIGURE 8) to the wheelbase or truck. The platform includes a tread portion 82 which is disposed at step height so that the operator in a single -step may mount or get off the platform. The platform is disposed, of course, adjacent to the control means or panel 75, and as best seen in FIGURE 8, and in FIGURE 1, is disposed outboard of the adjacent rail 16. The platform may be positioned substantially in line with the forward edge of the hatch cover 2.2, to enable the operator to view engagement of the cover onto the hatch opening. The platform is carried in a forward or foreand-aft spaced relation with respect to the hooks 12, 13

so Athat vbothof'themmay be simultaneously viewed from the control station.

Partially surrounding the tread portion 82, there is a hand rail 83 supported'by` 3 colums 84 or brackets shown in FIGURE 7. When the crane is not in use, the platformV 80 may be pivotcd as a whole to a storage position above and substantially inboard of the adjacent rail as shown in broken lines in FfGURE 8 whereby the 'Y walkway 20 is rendered unobstructed.

Referring now to FIGURES 1, 2, and 4, the means 14 for moving lthe hooks vertically will be explained. A first sheave 85 is disposed intermediate the beams 24, 25 and is provided with a fixed support `for its axis of rotation, such axis extending in a fore and aft direction. It is to be noted that this pulleyV or` sheave is 'disposed intermediate the beams 24, l25 and also above them. Similarly, sheaves 86 and 87 are likewise supported intermediate the beams 24, 25, their axes of rotation being fixed, extending in a fore-and-aft direction, and all such axes being horizontally spacedy yfrom each other.

Intermediate the sheaves 86 and 87 there is provided a fourth and fifth sheave `88, 89, the sheaves 88, 89, also -being disposed intermediate the beams 24, 25 and supported above them. Their rotational axes are parallel to the axes of the sheaves 85-87, and in this embodiment are aligned with each other. The sheaves 88, 89 are supported for rotation on a shaft 90 mounted in a yoke 91 which is connected to the movable end of a fluid actuator 92. The other end of the actuator 92 is se,- cured to the ybridge assembly 11 by means of a cross member 93. Preferably, the yoke 91 is provided with a pair of spaced rollers 94, `one on each side thereof for riding on the upper surface of the beams 24, 25 respectively. Thus the actuator 92 and yoke 91. comprise means for moving the sheaves 88, 89 to various positionsintermediate vthe sheaves 86, 87.

Suitable-lift cables 95, 96 are also included to cornprise part. of the means 14 for moving the `hooks 12 and 13 vertically. The routing of the cables 95, 96 is best seen in FIGURE 4. The first of these cables, 95, is secured at one end to a second cross member 97 supported on the upper surface of lthe beams 24, 25

for supporting the sheave` 85. Ihe lift cable 95 is thence directed through or around the sheaves 68 of the hook 12, thence around vthe first sheave 85, thence around the fourth sheave 88, while the other end is iixedly `secured to the cross member 93. The second lift cable 96 is secured to a third cross member 98 which is lalso used to support .the sheave 87, cable 96 `thence being directed around the sheave 68 of the hook 13, thence about the third sheave 87, thence about the second sheave S6, thence about the fifth sheave 89, its other end being also secured to the transverse member 93. When the huid actuator 92 is extended, the movable sheaves 88, 89. act on bights in the cables 95, 96 to lengthen such bights, thereby jointly retracting both hooks. Oppositemovement of .the actuator 92of course jointly lowers both of the hooks 12and 13.

In a structure such as the one disclosed, it is impractical .to us a hot or third rail for bringing in electric energy. Accordingly, an electric power cable 99, shown in' FIGURES, is employed to bring power fromthe ship to the crane. (For clarity, the cable has been omitted from FIGURES 1 `and 2.) To provide additional cable as needed, and to take up unused length of cable, a cable reel 100 is rotatably mounted on the upper surface of the bridge assembly. 11. The` cable reel 100 is powered and controlled for the automatic reelein and pay-outof cableV 99. To this end a uid motor 101 is co-rotatably connected t-o the drum of the cable reel 100. Operation and control of this motor is described below.

Referring now toV FIGURE l0, the various uid control circuits will be described. The source of pressurized fluid 74 includes an electric motor 102 powered by the power cable 99 (not shown in this FIGURE). The motor 102 may, for example, be of a 25-horsepower size, and.

is connecte-d to drive-two uid pumps 103, 104. The source of fluid pressure 74 also includes a sump diagrammatically shown in several places as 105 from which hydraulic fluid may be withdrawn, and to whichfit'may be returned. The pressurized fluid fromfthe pump 103 is directed through a relief valve 106 and thence to a line 107 to the drive motor 101 for the cable reel. From the motor 101, fluid is returned through a line 108 to the sump 105. A secon-d relief valve 109 is connected across the motor 101 to relieve pressure from the pump 103, and thereby to bypass liuid at the motor 101. The relief valve 106 keeps a predetermined output pressure on the pump 103. Fluid passing through theV relief kvalve 106 passes through the motor 101 iny such a direction as to wind power cable 99 onto the cable reel 100. When all slack has been taken up, the cable 99 applies an opposite torque to the cable reel 100, whereby the motor 101 is loaded further and stalled. This effects a pressure buildup on the upstream side of the motor, the extent of which is limited by the relief valve 109. The pressure being present on the motor, there is a continuous torque keeping the cable taut. 'If the crane be driven away from the end of the cable secured to the ship, the cable will actually rotate the motor 101 reversely so that it not only stalls it but overrides it. Conversely, when the crane is moved in the opposite direction, the drive motor 101 rotates the cable reel to take inV the cable as fast as it is made available. Thus by the provision of the relief valve 109 connected to the inlet -of the motor 101, any pressure above the normal reeling pressure is relieved, whereby power cable 99 is automatically reeled .in and paid out in response to crane movement. It is to be noted in FIGURE 3 that the power. cable 99 is preferably provided Vwith suitable rotatable guides orpulleys 110 to direct the cable as required.

The pump 104 is normally a somewhat larger` pump and provides Viiuid power for the remainder ofthe system. Pressurized fluid is directed from the pump 104 through a series of lines. 111-113 to the motor control means or directional valve 79, and through a pair of linesl 114, 115 to the actuator control means or directional valve 78. Ordinarily, fluid pressure passes through1the lines 111, 112, 113, is bypassed as shown through the-4-wayvalve 79, passes through the line 114, and is then first restricted at a relief valve 116. By way of example, this valve may create an upstream pressure of 65 pounds per square inch by restriction of flow. From the relief valve 116, fluid passes through the line 115, is bypassed as shown without appreciable restriction through the4way valve 78, and thence returned to the sump 105. .The hydraulic circuit includes two additional relief valves 117 and 118 whichwill not relieve pressure at the level created by the relief valve 116. Accordingly, `pressure builds :up in a line 119 leading to one side of each of the brake. actuators 44 which are so connected that a movement of the piston therein responsive to such buildup of pressure creates an output force which aids the `spring 43 to lock eachof the wheels 32 of the crane. Fluid on the other side of vthe piston in each ,of the actuators 44 is.v conducted by la line 120 through a bypass portion of the relief valve 11'7, without appreciable restriction,through a line.121.and thence to the line ,115. at a point downstream of the relief valve 116 which is substantially at sump pressure. When the valve 79 is in a neutral, bypassing, or centered posi.- tion, as shown, the actuators 44 will thus be urged vto the left or brake-setting position by the pressure inthe lines 112-114. The position. in which the actuators 44 are illustrated represents a brake-settingposition thereof. It is apparent that as brake bands wear, Vthe brake-setting position will be'further to the left. ,It is thus apparent that the line 119 taken with the relief valve 116 vflow-wise below it, comprise means responsivetoftluid pressure downstream of the valve 79 forV setting -the..brakes. Since the brakes are locked in a set position 'when the valve 79 is actuated to a left or to a right position for moving the crane in one Idirection or the other, the crane will not actually move at once, but instead the motors will momentarily be held in a stalled position by the brakes and there will be a pressure build-up in the line 113 which will be sensed by the relief valve 117. The stalled motors 34 also trap uid in lines 114, 119 at the pre-existing pressure. As the pressure is thus built up in the line 113, the slide in the relief valve 117 shifts to the right and the line 121 is closed ol from the line 120 within the relief valve 117 and the line 113 is communicated with the line 120. Thus built up pressure from the line 112 passes through the relief valve 117 to act on the opposite end of each of the actuators 44. When the built up pressure on this opposite end has increased suiciently to offset the force created by the pressure trapped on the other end of each actuator, and to offset the force produced by each of the springs 43 in each brake, each actuator 44 will shift to the right and release each of the brakes. Because of the relief valve 116, the pressure trapped on the first end of the actuators 44 will remain at that determined by such relief valve, but will be overpowered by a higher force from the opposite side or end. Thus there are means provided which are responsive to fluid pressure upstream of the valve 79 for releasing the brakes. In summary, the relief valve 117 is connected to the source of uid pressure at a point upstream from the directional valve 79, and is effective when operated to divert iluid therefrom only at a pressure higher than the pressure determined by the relief valve 116, to thereby direct fluid to the brake actuators 44 for release of the brakes.

The uid motors 34, while thus stalled initially block fluid flow, or effectively obstruct it when the directional valve 79 is first positioned to either crane-drive position, and thus tluid pressure builds up to release the brake after the fluid pressure has actually been applied directly to the drive motor. Fluid from the directional valve 79, when it is actuated and the brakes are released, passes through the aligned ports of the valve 79 in the direction of the arrowheads provided on each port, and thus passes first through a throttling valve 122, thence through the motor 34, and thence primarily through a check valve 123 which offers negligible resistance to flow of fluid. 'I'he fluid then ilows through the valve 79 into the line 114. `It will be noted that the operation of each of the motors 34 is identical in this respect for either operating position of the valve 79 which thereby effects rotation of the motors 34 in a selected direction, and hence movement ofthe crane on the rails in a selected direction.

When the valve 79 has been restored to a neutral or by-passing position, there is no appreciable obstruction to ow of hydraulic uid therethrough and hence the built up pressure will be relieved and the relief valve 117 will return to the-position shown and thus vent off the high pressure tluid from the line 120 and the one side of each of the brake actuators 44 to again permit the pressure in the line 119 to reset the brake.

When the directional valve 78 is actuated in one direction (to the right as illustrated), fluid passes through it at a rate determined by a throttling valve 124 and thence freely through a check valve 125 to one side of the actuator 92. In this embodiment, this pressure will effect a raising of the hooks 12, 13. Fluid on the other side of the piston in the actuator 92 is drained'by a line 126 through the va'lve 78 to the sump 105. A pair of valves 127, 128 explained below are closed during this operation. Assuming there is a load on the hooks 12, 13, such load will act to return the piston in the actuator 92. Reverse fluid ilow is blocked by the check valve 125 and is also blocked by the valve 127 and an additional valve 129. Thus a solid fluid cushion precludes lowering the hooks. When it is desired to deliberately lower the hooks, valve 78 is positioned in the opposite direction to supply pressure through the line 126 to the actuator 92. The valves 125, and 129, and 127 being closed, no immediate result takes place. However, at a selected rate determined by a throttling valve 130, a small amount of Huid is conducted therethrough to a diaphragm actuator or pilot mechanism 131 which gradually opens the shut-olf valve 129 to permit the lowering of the hooks. Thus the valve 129 with its actuator 131 comprise means responsive to load-lowering tluid pressure applied to the actuator 92 for delaying initiation of load-lowering movement thereof. Since the valve 129 is spring loaded as shown in the diagram, it normally blocks flow between the directional valve 78 and the end of the actuator 92 which is pressurized to raise the hooks. The check valve 125 thus by-passes the valve 129 to permit ow to the actuator for raising the hooks. Thus also the valve 129 is delayingly openable in response to pressure in the opposite side of the actuator.

It will be noted that the by-pass passage in the valve 79 is connected in series with the by-pass passage in the valve 78 so that normally uid is by-passed through both of these valves in series. In the event that the valve 78 be left in an open position after the actuator 92 has stopped movement, the pressure in the supply line will build up. Pressure in the supply line will also build up in the event that the motors 34 are stalled after release of the brakes. The relief valve 118 is thus set or selected for an appropriately higher relief pressure to return fluid to the sump under this type of condition to preclude damage to the system. Thus under any condition, the pump 104 may continuously run and may continuously deliver uid. Further, it may be expected that the trst one of the valves 78, 79 which is reached by tluid coming from the pump 104 wi'll be in the nature of a master whereby the operation of the second of such valves will effectively be precluded until the first of such valves has been restored to a by-pass condition. ln this embodiment, the valves 78, 79 comprise manually operated 4-way valves each provided with spring return to a neutral central bypassing condition.

It is to be understood that other components may be utilized to obtain equivalent results, and that where components are provided with drain ports, appropriate drain lines will be connected thereto for return to the sump.

In event of power failure, the springs 43 will tend to keep the crane locked in position on the rails. Likewise the check valve and the shut-olf valve 129, each being spring operated, will preclude the lowering of the hooks under load. To manually lower the load under this condition, the valve 127 may be manually opened to bleed olf lluid to the sump 105. Ordinarily, to prevent hydraulic locking and/ or cavitation it will be necessary also to open valve 128 to vent the opposite side of the actuator 92. To raise the hooks under conditions where power has failed, valve 128 is left open and the valve 127 is closed. A manually operated pump 132 acting through a check valve 133 may be employed to direct fluid through a line 134 to the actuator 92.

Although various minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon all such embodiments as reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

l. A crane for a hatch cover of a ship, the hatch cover having a pair of lifting means on the hatch cover each having a longitudinally directed hook-receiving opening, comprising in combination: a pair of rails adapted to be respectively supported on the deck at the starboard and port sides of the ship and extending fore and aft; a bridge extending transversely to said rails; a pair of rigid legs at each end of said bridge supporting said bridge on said rails for fore and aft movement thereon, said legs and bridge jointly defining a totally unobstructed clearance zone therebetween for accommodating ship structure; a pair of hooks supported at fixed positions along the 'length of said bridge intermediate said rails, and spaced from each other by a predetermined distance, each of said hooks opening in a single direction parallel to said rails and being adapted to be moved into and out of the respective longitudinally directed hook-receiving openings of the hatch cover lifting means in response to movement of said legs on said rails; and means carried by said bridge for moving said hooks vertically within said clearance zone.

2. A crane` for ahatch cover of a ship comprising in combination: a pair of rails adapted to be respectively supported on the deck at the starboard and port sides of the ship and extending fore and aft; a b-ridge extending transversely to said rails; a pair of rigid legs at each end of said bridge, each of the four legs having a wheel jointly Ymovably supporting said bridge on said rails, said legs and bridge jointly dening a totally unobstructed clearance zone therebetween for accommodating ship structure; a hydraulic motor for each of a plurality of said wheels and drivably connected thereto; a source of pressurized hydraulic -liuid supported on said crane in spaced relation to said clearance zone; control valve means connecting said source to said hydraulic motors in common for effecting fore and aft movement of the crane legs on said rails; a plurality of flow-rate control meansin series with said motors for equalizing iiuid flow to said wheel motors; hook means supported along the length of said bridge for establishing lifting engagement with the hatch cover; and means carried by said bridge for moving said hook means vertically within said clearance zone.

3. A crane for ahatch cover of a ship comprising in combination: a pair of rails adapted to be respectively supported on the deck at the starboard and port sides of the ship and extending fore and aft; a bridge extending transversely. to said rails; a pair of rigid legs at each end of said bridge, each of said legs having a Wheel jointly movably supporting said bridge on said rails, said legs and bridge jointly dening a totally unobstructed clearance zone therebetween for accommodating ship structure; drive means for rotatably driving said wheels for effecting fore and aft movement of the crane on said rails; sanding means carried by said crane legs and adapted to selectively discharge sand on said ship rails in the path ahead of said driven wheels; hook means supported at xed positions along the length of said bridge for establishing lifting engagement with the hatch cover; and means carried by said bridge for moving said hook means vertically Within said clearance zone.

4. A crane for a hatch cover of a ship comprising in combination: a pair of vrails adapted to be respectively supported on the deck at the starboard and port sides of the ship and extending fore and aft; a bridge extending transversely to said rails; a pair of rigid legs at each end of said bridge, each of said legs having a wheel jointly movably supporting said bridge on said rails, said legs and bridge jointly defining a totally unobstructed 4clearance zone therebetween for accommodating ship structure; drive means for rotatably driving said wheels for effecting fore and aft movement of the crane on said rails; hook means supported along the length of said bridge for establishing lifting engagement with the hatch cover; means carried` by said bridge for moving said hook means vertically Within said clearance Zone; a power cable adapted to be connected between the ship and .said bridge for conducting power to at least one of said wheel drive means and said hook moving means;,and a cable reel` carried by said bridge and adapted to automatically reel in and pay out said cable in response to movement of said'bridge on said rails, said cable also providing the necessary reel-in power to said cable reel.

5. A crane for a'hatch cover of a ship comprising in combination: .a pair of rails adapted to be respectively supported on the deck at the starboard and port sides of the ship and extending fore and aft; a bridge extending transversely to said rails; a pair of rigid legs at each end of said bridge; a pair of wheelbases each rigidly respectively secured centrally thereof to one pair of said pair of legs, each of said wheelbases having a plurality of wheels disposed respectively at the ends thereof and jointly movably supporting said bridge on said rails, said legs and bridge jointly defining a totally unobstructed clearance zone therebetween for accommodating ship structure; drive means for rotatably driving said wheels for effecting fore and aft movement of the crane on said rails; hook means supported along the length of said bridge intermediate said rails, said hook means opening in a direction parallel to said rails for establishing lifting engagement with the hatch cover in response to movement of said Wheels on said rails; means carried by said bridge for moving said hook means vertically within said `clearance zone; and an operators platform hingedly supported iby one of said lwheelbases at the inboard side thereof and disposed at step height adjacent to both of said control means intermediate one of said rails and the adjacent side of the ship, said platform having a railing rigidly secured thereto and being pivotable to a storage position where said railing is stored above said one wheelbase and substantially entirely inboard of said one rail to eliminate obstruction of a walkway on the ships deck intermediate said one rail and said adjacent side of the ship.

6. A crane for a ship comprising in combination: a pair of rails adapted to be `supported on the ships deck adjacent respectively to the starboard and port sides of the ship and extending fore and aft; a bridge extending transversely to said rails; a pair of rigid legs at each end of said bridge rigidly supporting said bridge on said rails for fore and aft movement thereon, the inner periphery of said legs and bridge jointly dening a totally unobstructed clearance zone therebetween for accommodating ship structure; hook means supported by and always disposed Within the length of said bridge intermediate said rails; means carried by said bridge for moving said hook means vertically through said clearance zone; and at least one pair of auxiliary Outrigger members independent of said hook means and supported on said bridge above said clearance zone in fore-and-aft adjacently spaced relation to each other, said members being disposed substantially parallel to said bridge and being slidably extendable therefrom while so supported for positioning the respective free ends thereof in overhanging relationship beyond the adjacent side of the ship without translating said hook means.

7. In a crane including an elongated supported bridge, hook means dependingly supported along the length of said bridge, and hydraulically actuated means carried by said bridge for raising said hook means, said hook means Y being liftable to such an extent that an article being hoisted thereby could engage the lower surface of said bridge, the improvement comprising in combination therewith of resilient rubber bumper means each having a horizontally directed hollow cylindrical configuration ixedly secured to the lower surface of said bridge in downwardly extending relation and disposed adjacent to said hook means and directed to be engaged only by the hoisted hook-supported article.

8. A crane for a hatch cover of a ship comprising in combination: a pair of rails adapted to be respectively supported on the deck at the starboard and port sides of the ship and extending fore and aft; a bridge structure including a pair of parallel fore-and-aft spaced beams extending transversely to said rails; a pair of rigid leg assemblies at each end of said bridge structure supporting said beams in fixed relation to each other and movably on said rails for fore and aft movement thereon, said leg assemblies and bridge structure jointly defining a totally unobstructed clearance zone therebetween for accommodating ship structure; a first, a second, and a third sperano sheave each rotatably supported about fixed horizontally spaced fore-and-aft axes and disposed intermediate the upper surfaces of said beams; a fourth and a fifth sheave rotatably supported about a fore-and-aft axis and disposed intermediate the upper surfaces of said beams intermediate said second and third sheaves; means for selectively moving said fourth and fifth sheaves to various positions intermediate said second and third sheaves; a first and a second sheaved-hook assembly, the hooks thereof being non-rotatable about a vertical axis and opening in a direction parallel to said rails; a first and a second lift cable; said first lift cable being flxedly connected at both ends to said bridge structure, and directed through said first sheaved-hook assembly, and about said first and fourth sheaves; said second cable being flxedly connected at both ends to said bridge structure, and directed through said second sheaved-hook assembly, and about said third, second, and fifth sheaves; said sheavedhook assemblies being jointly retractible to positions intermediate of and above the bottom surfaces of said beams.

9. In a crane having an elongated bridge, means secured to said crane for moving said bridge horizontally in opposite directions transverse to its longest dimension, hook means dependingly supported along the length of said bridge, and means carried by said bridge for selectively moving said hook means vertically, the improvement in combination therewith, comprising: a power cable for connecting a stationary source of power to at least one of said bridge-moving means and said hook-moving means; a cable reel carried by the crane for reeling in and paying out said cable in response to bridge movement; a fluid motor thaving an inlet adapted to be connected to a source of fluid pressure, said motor being drivingly coupled to said cable reel for continuously applying a torque to said cable reel; and a fluid relief valve connected to said motor inlet and adapted to relieve fluid pressures exceeding the pressure needed to drive said motor under normal reeling load; said motor being stallable and overridable by torque applied thereto by said cable via said cable reel in response to movement of said bridge in one of said directions; whereby said reeling in and paying out of said cable is automatically effected as needed.

l0. A crane having selectably movable hook means, said crane comprising in combination: an elongated bridge assembly supporting said hook means and adapted to be moved horizontally in opposite directions transverse to its longest dimension; fluid motor means operatively connected to said bridge assembly for moving said bridge assembly in said directions; fluid brake means operatively connected to said bridge assembly for precluding movement by said bridge assembly in said directions; a source of fluid pressure supported on said bridge assembly; a directional valve selectively communicating said source of fluid pressure with said fluid motor means to effect operation thereof in opposite directions, and to effect bypassing of pressurized fluid; a first relief valve connected to the outlet of said directional valve for maintaining a predetermined minimum pressure upstream of said relief valve; said fluid brake means being supplied with fluid at said predetermined pressure from a point intermediate said directional valve and said relief valve to effect braking; and a second relief valve connected to said source of fluid pressure at a point upstream from said directional valve and adapted to divert fluid therefrom only a at pressure greater than said predetermined pressure and to direct it to said fluid brake means for release of said brake means; said fluid motor means, in response to actuation of said directional valve to a drive position, being operative to initially obstruct uid flow therethrough and thereby to effect a buildeup of said greater pressure for effecting release of said brake means after fluid pressure begins to drivingly act on said fluid motor means.

ll. A crane having selectably movable hook means, said crane comprising in combination: an elongated bridge assembly supporting said hook means and adapted to be moved horizontally in opposite directions transverse to its longest dimension; fluid motor means operatively connected to said bridge assembly for moving said bridge assembly in said directions; fluid brake means operatively connected to said bridge assembly for precluding movement by said bridge assembly in said directions; a source of fluid pressure supported on said bridge assembly; a directional valve selectively communicating said source of fluid pressure with said fluid motor means to effect operation thereof in opposite directions, and to effect bypassing of pressurized fluid; means responsive to fluid pressure downstream of said valve for effecting setting of said fluid brake means; and means responsive to fluid pressure upstream of said valve for effecting releasing of said fluid brake means.

l2. A crane comprising in combination: an elongated bridge assembly adapted to be moved horizontally in opposite directions transverse to its longest dimension; hook means dependingly supported from said bridge assembly for raising and lowering loads therebeneath; a fluid actuator supported by said bridge assembly and operatively connected to said hook means for effecting said raising and lowering; fluid motor means operatively connected to said bridge assembly for moving said bridge assembly in said directions; fluid brake means operatively connected to said bridge assembly for precluding movement by said bridge assembly in said directions; a source of fluid pressure supported on said bridge assembly; a pair of directional valves, the first of said valves selectively communicating said source of fluid pressure with said fluid motor means to effect operation thereof in opposite directions, and to effect bypassing of pressurized fluid; the second of said valves selectively communicating said source of fluid pressure with opposite ends of said fluid actuator to effect operation thereof in opposite directions, and to effect bypassing of pressurized fluid; said valves being so connected in series that fluid bypassed through one'of said valves is normally also bypassed through the other of said valves; means responsive to fluid pressure downstream of said first valve for effecting setting of said fluid brake means; and means responsive to fluid pressure upstream of said first valve for effecting releasing of said fluid brake means.

13. A crane for a hatch cover of a ship comprising 1n combination: a pair of rails adapted to be respectively supported on the deck at the starboard and port sides of the ship and extending fore and aft; a bridge extending transversely to said rails; a pair of rigid legs at each end of said bridge, each of the four legs having a wheel jointly movably supporting said bridge on said rails, said legs and bridge jointly defining a totally unobstructed clearance zone therebetween for accommodating ship structure; a hydraulic motor for each of a plurality of said wheels and drivably connected thereto; a source of pressurized hydraulic fluid supported on said crane in' spaced relation to said clearance zone; control valve means connecting said source to said hydraulic motors in common for effecting fore and aft movement of the crane legs on said rails; a plurality of flow-rate control means in series with said motors for equalizing fluid flow to said wheel motors; sanding means carried by said crane legs and adapted to selectively discharge sand on said ship rails in the path ahead of said driven wheels; a pair of resilient rubber bumpers each having a horizontally directed hollow cylindrical configuration fixedly secured to said bridge in spaced relation to each other and extending below the lower surface of said bridge slightly into said clearance zone and disposed to be engaged only by the hatch cover; a pair of hooks supported at fixed positions along the length of said bridge intermediate said rails, and respectively adjacent to said bumpers, and spaced from each other by a predetermined distance, each of said hooks opening in a single direction parallel to said rails and being adapted to be moved into 13 and out of lifting relation with the hatch cover in response to movement of said legs on said rails; means carried by said bridge for moving said hooks vertically within said clearance zone to raise the hatch cover into engagement with said bumpers; a power cable adapted to be connected between the ship and said bridge for conducting power to at least one of said source of hydraulic pressure and said hook moving means; and a cable reel carried by said crane bridge and adapted to automatically reel in and pay out said cable in response to movement of said bridge on said rails, said cable also providing the necessary reel-in power to said cable reel.

References Cited in the le of this patent UNITED STATES PATENTS Pirtle Dec. 17, 1907 Boynton Nov. 22, 19'10 Wood Feb. 12, 1929 Brinley Mar. 8, 1932 Diaz Aug. 5, 1947 Andersen Dec. 14, 19418 Speer Feb. 13, 1951 Minty Sept. 29, 1959 

